TY - JOUR AU - Buchholz, Peter AU - Mészáros, András Gergely AU - Telek, Miklós TI - Stationary analysis of a constrained Markov fluid model with two buffers JF - STOCHASTIC MODELS J2 - STOCH MODELS PY - 2024 SN - 1532-6349 DO - 10.1080/15326349.2024.2339247 UR - https://m2.mtmt.hu/api/publication/34832881 ID - 34832881 N1 - Export Date: 3 May 2024 Correspondence Address: Mészáros, A.; Department of Networked Systems and Services, Hungary; email: meszarosa@hit.bme.hu AB - Abstract.: We consider Markov fluid models with two infinite buffers, whose fluid rates ensure that the fluid level of buffer 1 is never larger than the one of buffer 2. For the model, we derive the system of PDEs describing the transient behavior and expressions for the stationary analysis in the Laplace domain. Examples for the application of the model in the context of network access control are presented. Numerical results are compared with detailed simulation results to show that the numerical approach computes the required measures with sufficient accuracy. © 2024 Taylor & Francis Group, LLC. LA - English DB - MTMT ER - TY - JOUR AU - Mészáros, András Gergely AU - Telek, Miklós TI - Numerical inverse transformation of double sided Laplace transform with parameter optimization JF - APPLIED MATHEMATICS AND COMPUTATION J2 - APPL MATH COMPUT VL - 474 PY - 2024 PG - 15 SN - 0096-3003 DO - 10.1016/j.amc.2024.128713 UR - https://m2.mtmt.hu/api/publication/34785835 ID - 34785835 N1 - Export Date: 12 April 2024 CODEN: AMHCB Correspondence Address: Telek, M.; Department of Networked Systems and Services, Hungary; email: telek@hit.bme.hu AB - There are efficient numerical inverse Laplace transformation (NILT) procedures for double sided Laplace transforms (DSLT), which are based on some hyperparameters. If those hyperparameters are set properly, the computed inverse is accurate, while using an incorrect hyperparameter results in a completely incorrect inverse. To the best of the authors knowledge, there is no NILT procedure for DSLT, which automatically sets the hyperparameters based on the DSLT and the point where the inverse needs to be computed. In this paper we propose a procedure which automatically optimizes the hyperparameters of the NILT method and this way it eliminates the unforeseen dependency of the computed inverse on the inherent hyperparameters. © 2024 Elsevier Inc. LA - English DB - MTMT ER - TY - JOUR AU - Mészáros, András Gergely AU - Telek, Miklós TI - Moments based matrix representation of Markov and rational arrival processes with reduced rank marginal JF - STOCHASTIC MODELS J2 - STOCH MODELS PY - 2024 SN - 1532-6349 DO - 10.1080/15326349.2023.2253289 UR - https://m2.mtmt.hu/api/publication/34149140 ID - 34149140 N1 - Export Date: 21 September 2023 Correspondence Address: Telek, M.; Department of Networked Systems and Services, Hungary; email: telek@hit.bme.hu LA - English DB - MTMT ER - TY - JOUR AU - Almousa, Salah Al-Deen Afif Said AU - Horváth, Gábor AU - Telek, Miklós TI - Correction to: Transient analysis of piecewise homogeneous Markov fluid models (Annals of Operations Research, (2020), 10.1007/s10479-020-03831-1) JF - ANNALS OF OPERATIONS RESEARCH J2 - ANN OPER RES VL - 332 PY - 2024 SP - 1251 EP - 1251 PG - 1 SN - 0254-5330 DO - 10.1007/s10479-021-03934-3 UR - https://m2.mtmt.hu/api/publication/32242266 ID - 32242266 N1 - Correction to: Annals of Operations Research https://doi.org/10.1007/s10479-020-03831-1 [31797535] AB - Affiliation for author Miklos Telek was missing in the original publication and should be read as: Department of Networked Systems and Services, Budapest University of Technology and Economics, Budapest, Hungary and MTA-BME Information Systems Reseach Group, Hungary. Along with Department of Networked Systems and Services, Budapest University of Technology and Economics, Budapest, Hungary. Original article has been updated. © 2021, Springer Science+Business Media, LLC, part of Springer Nature. LA - English DB - MTMT ER - TY - JOUR AU - Schranz, Ágoston AU - Solymos, Balázs AU - Telek, Miklós TI - Stochastic performance analysis of a time-of-arrival quantum random number generator JF - IET Quantum Communication PY - 2023 PG - 17 SN - 2632-8925 DO - 10.1049/qtc2.12080 UR - https://m2.mtmt.hu/api/publication/34448296 ID - 34448296 N1 - Department of Networked Systems and Services, Faculty of Electrical Engineering and Informatics, Budapest University of Technology and Economics, Budapest, Hungary ELKH-BME Information Systems Research Group, Budapest, Hungary Export Date: 22 December 2023 Correspondence Address: Schranz, Á.; Department of Networked Systems and Services, Hungary; email: schranz.agoston@vik.bme.hu Funding details: 2022–2.1.1‐NL‐2022‐00004, K‐142845 Funding details: Hungarian Scientific Research Fund, OTKA, K‐138208 Funding details: Nemzeti Kutatási Fejlesztési és Innovációs Hivatal, NKFI Funding text 1: The authors are thankful for the fruitful discussions and the advises of Illés Horváth (ELKH‐BME Information Systems Research Group, Budapest, Hungary). M. Telek was supported by the OTKA K‐138208 project of the Hungarian Scientific Research Fund. B. Solymos and Á. Schranz were supported by the Ministry of Culture and Innovation and the National Research, Development and Innovation Office within the Quantum Information National Laboratory of Hungary (Grant No. 2022–2.1.1‐NL‐2022‐00004). Á. Schranz was also supported by the OTKA K‐142845 project of the Hungarian Scientific Research Fund. AB - The performance analysis of a quantum random number generator (QRNG), operating based on the interarrival time differences between consecutive photon detections from a coherent light source, is presented. The proposed analysis approach accurately takes into account the physical properties of the single-photon detection systems, such as discretised time measurement, the correlations induced by the asynchronous arrival of photons with respect to the time resolution grid, and the dead time after observations and provides the QRNG's relevant performance measures, such as the joint distribution of bits, lag-r correlations, the bit generation overhead and the bit generation time. Analysis results are verified by computer simulations. © 2023 The Authors. IET Quantum Communication published by John Wiley & Sons Ltd on behalf of The Institution of Engineering and Technology. LA - English DB - MTMT ER - TY - CHAP AU - Buchholz, P. AU - Mészáros, András Gergely AU - Telek, Miklós ED - Iacono, M. ED - Scarpa, M. ED - Serrano, S. ED - Longo, F. ED - Barbierato, E. ED - Cerotti, D. TI - Analysis of a Two-State Markov Fluid Model with 2 Buffers VL - 14231 LNCS PB - Springer Science+Business Media SN - 9783031431845 T3 - Lecture Notes in Computer Science, ISSN 0302-9743 ; 14231 LNCS. PY - 2023 SP - 49 EP - 64 PG - 16 DO - 10.1007/978-3-031-43185-2_4 UR - https://m2.mtmt.hu/api/publication/34342460 ID - 34342460 N1 - Export Date: 16 November 2023 Correspondence Address: Telek, M.; Department of Networked Systems and Services, Hungary; email: telek@hit.bme.hu LA - English DB - MTMT ER - TY - CHAP AU - Saffer, Z. AU - Grill, K. AU - Telek, Miklós ED - Iacono, M. ED - Scarpa, M. ED - Serrano, S. ED - Longo, F. ED - Barbierato, E. ED - Cerotti, D. TI - M/G/1 Queue with State Dependent Service Times VL - 14231 LNCS PB - Springer Science+Business Media SN - 9783031431845 T3 - Lecture Notes in Computer Science, ISSN 0302-9743 ; 14231 LNCS. PY - 2023 SP - 81 EP - 95 PG - 15 DO - 10.1007/978-3-031-43185-2_6 UR - https://m2.mtmt.hu/api/publication/34342456 ID - 34342456 N1 - Export Date: 16 November 2023 Correspondence Address: Saffer, Z.; Institute of Statistics and Mathematical Methods in Economics, Austria; email: zsolt.saffer@tuwien.ac.at LA - English DB - MTMT ER - TY - JOUR AU - Fodor, Sebastian AU - Fodor, Gábor AU - Gurgunoglu, Doga AU - Telek, Miklós TI - Optimizing Pilot Spacing in MU-MIMO Systems Operating Over Aging Channels JF - IEEE TRANSACTIONS ON COMMUNICATIONS J2 - IEEE T COMMUN VL - 71 PY - 2023 IS - 6 SP - 3708 EP - 3720 PG - 13 SN - 0090-6778 DO - 10.1109/TCOMM.2023.3261384 UR - https://m2.mtmt.hu/api/publication/34085465 ID - 34085465 N1 - Funding Agency and Grant Number: H2020 Marie Sklodowska-Curie Innovative Training Networks [956256]; Celtic Project 6G for Connected Sky [C2021/1-9]; Hungarian Scientific Research Fund OTKA [K-138208] Funding text: Gabor Fodor was partially supported by the H2020 Marie Sklodowska-Curie Innovative Training Networks, GA Number: 956256, and also partially supported by the Celtic Project 6G for Connected Sky, Project ID: C2021/1-9. Doga Gurgunoglu was partially supported by the H2020 Marie Sklodowska-Curie Innovative Training Networks, GA Number: 956256. Miklos Telek is partially supported by the Hungarian Scientific Research Fund OTKA K-138208 project. The associate editor coordinating the review of this article and approving it for publication was L. Sanguinetti.& nbsp; AB - In the uplink of multiuser multiple input multiple output (MU-MIMO) systems operating over aging channels, pilot spacing is crucial for acquiring channel state information and achieving high signal-to-interference-plus-noise ratio (SINR). Somewhat surprisingly, very few works examine the impact of pilot spacing on the correlation structure of subsequent channel estimates and the resulting quality of channel state information considering channel aging. In this paper, we consider a fast-fading environment characterized by its exponentially decaying autocorrelation function, and model pilot spacing as a sampling problem to capture the inherent trade-off between the quality of channel state information and the number of symbols available for information carrying data symbols. We first establish a quasi-closed form for the achievable deterministic equivalent SINR when the channel estimation algorithm utilizes multiple pilot signals. Next, we establish upper bounds on the achievable SINR and spectral efficiency, as a function of pilot spacing, which helps to find the optimum pilot spacing within a limited search space. Our key insight is that to maximize the achievable SINR and the spectral efficiency of MU-MIMO systems, proper pilot spacing must be applied to control the impact of the aging channel and to tune the trade-off between pilot and data symbols. LA - English DB - MTMT ER - TY - JOUR AU - Horváth, Illés AU - Mészáros, András Gergely AU - Telek, Miklós TI - Numerical inverse Laplace transformation beyond the Abate–Whitt framework JF - JOURNAL OF COMPUTATIONAL AND APPLIED MATHEMATICS J2 - J COMPUT APPL MATH VL - 418 PY - 2023 PG - 12 SN - 0377-0427 DO - 10.1016/j.cam.2022.114651 UR - https://m2.mtmt.hu/api/publication/33091248 ID - 33091248 N1 - ELKH-BME Information Systems Research Group, Budapest, Hungary Department of Networked Systems and Services, Budapest University of Technology and Economics, Budapest, Hungary Export Date: 13 September 2022 Correspondence Address: Horváth, I.; ELKH-BME Information Systems Research GroupHungary; email: pollux@math.bme.hu AB - Among the numerical inverse Laplace transformation (NILT) methods, those that belong to the Abate–Whitt framework (AWF) are considered to be the most efficient ones currently. It is a characteristic feature of the AWF NILT procedures that they are independent of the transform function and the time point of interest. In this work we propose an NILT procedure that goes beyond this limitation and optimize the accuracy of the NILT utilizing also the transform function and the time point of interest. LA - English DB - MTMT ER - TY - CONF AU - Mészáros, András Gergely AU - Telek, Miklós TI - Moments based characterization of MAPs with reduced rank marginal T2 - Proceedings of the 11th Matrix-Analytic Methods in Stochastic Models conference (MAM11) PY - 2022 SP - 1 PG - 4 UR - https://m2.mtmt.hu/api/publication/33666829 ID - 33666829 LA - English DB - MTMT ER -